The primary objective of this research is to gain better understanding of the molecular mechanism of gene expression in animal cells. In these cells the first step of gene activity is the transcription of a DNA sequence into an RNA sequence in the nucleus, with an essential late step, the translation of part of that RNA sequence into a protein in the cytoplasm. Between these two steps the RNA undergoes several modifications and has to migrate from the nucleus to the cytoplasm. The purpose of the specific project supported by this grant is to isolate enzymes that might be involved in catalyzing some of the modifications that occur. Since it is difficult to devise direct assays for some enzymes, the approach that will be used is to isolate an enzyme that will catalyze the hydrolysis of ATP to ADP and Pi only in the presence of RNA. Such an activity has been detected in nuclei of animal cells and attempts are being made to isolate the enzyme in pure form and to determine its normal localization within the nucleus. Once the enzyme is isolated, tests for its function will be made by studying its effects of RNA intermediates isolated from nuclei and on the synthesis of RNA in vivo using purified animal cell RNA polymerase and DNA from an animal virus (adenovirus).